This invention relates to a novel valve with a pulsation damping device.
In case, in which an end-closed measuring instrument such as a pressure gauge is connected with a fluid pressure generating apparatus as a reciprocating pump by means of a pipe for measuring the pressure thereof, the needle of the measuring instrument fluctuates owing to the pulsation caused by the reciprocating pump, making the measurement of the pressure difficult and the measuring instrument easily broken down.
In order to prevent such influence of the pulsation on the measuring instrument as shown by said fluctuation of the needle thereof, generally a pulsation damping apparatus is inserted to the pipe.
Such conventional pulsation damping apparatus are provided with a valve stem having a needle-like valve part and damp pulsation by adjusting the gap between the valve part and the corresponding valve seat. In such a mechanism, the change of the throttle resistance of the gap with the rotation of the valve stem is shown to be curved in characteristics. Therefore, as will be discribed below, it is impossible to damp the pulsation effectively by using said conventional pulsation damping apparatus.
This invention has been devised to overcome the defects of the conventional pulsation damping apparatus as described hereinabove.